N-Benzylaziridine is conventionally prepared by reacting benzyl chloride or bromide with aziridine (ethylenimine). The process is conducted in a polar solvent (e.g. methanol) and in the presence of an acid acceptor and/or an excess of aziridine reactant. See "Ethylenimine and Other Aziridines" by O. C. Dermer and G. E. Ham, Academic Press, Inc., N. Y. (1969) pages 125-6.